Altitude hold limit

[dresoccer4]

Is there an altitude limit for the alititude hold autopilot? I'm around FL350 and the altitude AP lights come on but she don't hold the altitude. Keeps slowly nosing up or down. 

[isglas]

12 hours ago, dresoccer4 said:

Is there an altitude limit for the alititude hold autopilot? I'm around FL350 and the altitude AP lights come on but she don't hold the altitude. Keeps slowly nosing up or down. 

At what speed did you hav it on because mach tuck is modeled in the viggen 

[razo+r]

No issues here. It held the altitude steadily up to 12km altitude above and below M1.0.

[MYSE1234]

13 hours ago, dresoccer4 said:

Is there an altitude limit for the altitude hold autopilot? I'm around FL350 and the altitude AP lights come on but she don't hold the altitude. Keeps slowly nosing up or down. 

That should not be a problem for it, as others have said it works without problem at that altitude. What it sounds like to me is that it's speed related, you were probably too slow for it to keep control of the aircraft properly is my guess.

[TOViper]

Or he maybe engaged it in the transonic regime? FL350 means he had to fly at higher sub-sonic Machnumber to keep her up flying ...